package com.app.script;

import java.lang.reflect.Array;
import java.math.BigDecimal;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

public class ExpressionEvaluator {

    public boolean evaluateBoolean(String expression, Object parameterObject) {
        Object value = OgnlCache.getValue(expression, parameterObject);
        if (value instanceof Boolean)
            return (Boolean) value;
        if (value instanceof Number)
            return !new BigDecimal(String.valueOf(value))
                    .equals(BigDecimal.ZERO);
        return value != null;
    }

    public Iterable<?> evaluateIterable(String expression,
                                        Object parameterObject) {
        Object value = OgnlCache.getValue(expression, parameterObject);
        if (value == null)
            throw new RuntimeException("The expression '" + expression
                    + "' evaluated to a null value.");
        if (value instanceof Iterable)
            return (Iterable<?>) value;
        if (value.getClass().isArray()) {
            // the array may be primitive, so Arrays.asList() may throw
            // a ClassCastException (issue 209). Do the work manually
            // Curse primitives! :) (JGB)
            int size = Array.getLength(value);
            List<Object> answer = new ArrayList<Object>();
            for (int i = 0; i < size; i++) {
                Object o = Array.get(value, i);
                answer.add(o);
            }
            return answer;
        }
        if (value instanceof Map) {
            return ((Map) value).entrySet();
        }
        throw new RuntimeException("Error evaluating expression '" + expression
                + "'.  Return value (" + value + ") was not iterable.");
    }

}
